Henry Darcy developed Darcy's law in 1856 based on experiments studying the flow of water through sand filters. Darcy's law states that for laminar flow through saturated soil or porous media, the discharge rate is proportional to the hydraulic gradient. The law is expressed mathematically as Q=KA(h1-h2)/L, where Q is the flow rate, K is the hydraulic conductivity, A is the cross-sectional area, h1 and h2 are the water levels, and L is the distance between them. Darcy's law is valid for laminar flow in saturated, homogeneous, isotropic porous media, but may not apply to turbulent or unsaturated flow conditions. It has wide applications in areas like

1. Presentation
On
DARCY’S LAW
Presented by:
Md Imran HossainRakib
Roll No -18531045
Course code-
BangladeshUniversityOf Professionals

2. WHO WAS DARCY?
• Henry Philibert Gaspard Darcy was born June 10,
1803 in Dijon, France.
• Admitted to the French School of Bridges and Roads in
Paris, part of the Corps of Bridges and Roads. After
graduation, he was eventually assigned by the Corps to
a position in Dijon.
• In 1828, Darcy designed a 12.7 km system of aqueducts
to supply the city of Dijon with surface water. The
system included 28,000 m of pressurized surface lines
and required no pumps or filters.

3. • Made important contributions to flow
and friction loss in pipes, created an
improved pitot tube design, and was
the first to postulate the existence of a
boundary layer in fluid flow.
• In 1856, carried out experiments
while researching sand filters that
lead to Darcy’s Law.
Henry Philibert Gaspard Darcy (1803–1858)

4. DARCY’S LAW
• The law of flow of water through soil was
first studied by Darcy in 1856.
• The Darcy’s law is,
“For laminar flow through saturated soil
mass, the discharge per unit time is
proportional to the hydraulic gradient”.

5. Equation
• Q=KA(h1-h2)/L
Here,
Q is Flow rate
A is area
H1,h2 are groundwater heads
K is the hydraulic conductivity
L is distance between groundwater heads.

7. ASSUMPTIONS OF DARCY’S LAW :-
The following assumptions are made in Darcy’s
law:
• The soil is saturated.
• The flow through soil is laminar.
• The flow is continuous and steady.
• The total cross sectional area of soil mass is
considered.
• The temperature at the time of testing is 270C.

8. VALIDITY OF DARCY’S LAW
1. Darcy’s law is valid if the flow through soils is
laminar :
• The flow of water through soils depends upon the
dimension of particles. In fine grained soils the
dimensions of the interstices (voids) are very
small and flow is necessarily laminar.
• In course- grained soil, the flow is also laminar.
However, in very coarse grained soils, such as

9. 2.As per Allen Hazen, the maximum diameter of the
particle for the flow to be laminar is about 0.50 mm.
3. It is valid for flow in clays, slits and fine sands. In
coarse sands, gravels and boulders, the flow may be
turbulent and Darcy’s law may not be applicable.
4. For Darcy’s law to be valid, the relationship
between velocity (v) and hydraulic gradient(i)
should be linear.
5. In extremely fine-grained soils, such as colloidal

10. Limitations of Darcy’s Law
• Due to skin formation permeability in vicinity
of wellbore is changing (decreasing)
• At higher flow rates inertial force, acting due
to convective acceleration of fluid particles
through porous medium, have to be taken into
account.

11. Application Of Darcy’s Law
• The study of flow in porous media is important in a wide range of
applications including-
Ground water flow
Exploitation of petroleum reservoirs
Filter design
Capillary circulation
Chemical reactors

12. Thank You